Access Control Synthesis for Physical Spaces

Access-control requirements for physical spaces, like office buildings and airports, are best formulated from a global viewpoint in terms of system-wide requirements. For example, "there is an authorized path to exit the building from every room." In contrast, individual access-control components, such as doors and turnstiles, can only enforce local policies, specifying when the component may open. In practice, the gap between the system-wide, global requirements and the many local policies is bridged manually, which is tedious, error-prone, and scales poorly. We propose a framework to automatically synthesize local access control policies from a set of global requirements for physical spaces. Our framework consists of an expressive language to specify both global requirements and physical spaces, and an algorithm for synthesizing local, attribute-based policies from the global specification. We empirically demonstrate the framework's effectiveness on three substantial case studies. The studies demonstrate that access control synthesis is practical even for complex physical spaces, such as airports, with many interrelated security requirements

An Anti-Pattern for Misuse Cases

Misuse case analysis is a method for the elicitation, documentation, and communication of security requirements. It builds upon the well-established use case analysis method and is one of the few existing techniques dedicated to security requirements engineering. We present an anti-pattern for applying misuse cases, dubbed “orphan misuses.” Orphan misuse cases by and large ignore the system at hand, thus providing little insight into its security. Common symptoms include implementation-dependent threats and overly general, vacuous mitigations. We illustrate orphan misuse cases through examples, explain their negative consequences in detail, and give guidelines for avoiding them

Reconstructing the Poynting vector skew angle and wave-front of optical vortex beams via two-channel moir\'e deflectometery

A novel approach based on the two-channel moir\'e deflectometry has been used to measure both wave-front and transverse component of the Poynting vector of an optical vortex beam. Generated vortex beam by the q-plate, an inhomogeneous liquid crystal cell, has been analyzed with such technique. The measured topological charge of generated beams are in an excellent agreement with theoretical prediction.Comment: 3 pages, 2 figure

Minimal Message Complexity of Asynchronous Multi-party Contract Signing

Multi-party contract signing protocols specify how a number of signers can cooperate in achieving a fully signed contract, even in the presence of dishonest signers. This problem has been studied in different settings, yielding solutions of varying complexity. Here we assume the presence of a trusted third party that will be contacted only in case of a conflict, asynchronous communication, and a total ordering of the protocol steps. Our goal is to develop a lower bound on the number of messages in such a protocol. Using the notion of abort chaining, a specific type of attack on fairness of signing protocols, we derive the lower bound α 2 + 1, with α &gt; 2 being the number of signers involved. We obtain the lower bound by relating the problem of developing fair signing protocols to the open combinatorial problem of finding shortest permutation sequences. This relation also indicates a way to construct signing protocols which are shorter than state-of-the-art protocols. We illustrate our approach by presenting the shortest three-party fair contract signing protocol.</p

Zeolite-silver-zinc nanoparticles : biocompatibility and their effect on the compressive strength of mineral trioxide aggregate

This study was carried out to evaluate the biocompatibility of zeolite-silver-zinc (Ze-Ag-Zn) nanoparticles and their effect on the compressive strength of Mineral Trioxide Aggregate (MTA). Biocompatibility was evaluated by an MTT assay on the pulmonary adenocarcinoma cells with 0.05, 0.1, 0.25, 0.5, 1 and 5 mg/mL concentrations of Ze-Ag-Zn. For compressive strength test, four groups containing 15 stainless-steel cylinders with an internal diameter of 4 and a height of 6 mm were prepared and MTA (groups 1 and 2) or MTA + 2% Ze-Ag-Zn (groups 3 and 4) were placed in the cylinders. The compressive strength was evaluated using a universal testing machine 4 days after mixing in groups 1 and 3, and 21 days after mixing in groups 2 and 4. There was no significant difference between cytotoxicity of different concentrations. The highest (52.22±18.92 MPa) and lowest (19.57±5.76 MPa) compressive strength were observed in MTA group after 21 days and in MTA + 2% Ze-Ag-Zn group after four days, respectively. The effect of time and 2% Ze-Ag-Zn on the compressive strength were significant (P<0.05). Mixing MTA with Ze-Ag-Zn significantly reduced and passage of time from day four to 21 significantly increased the compressive strength. Mixing MTA with 2% Ze-Ag-Zn had an adverse effect on the compressive strength of MTA, but this combination had no cytotoxic effects

Circulating levels of novel adipocytokines in patients with colorectal cancer

Objective: Adipocytokines have been reported to contribute to the pathogenesis of colorectal cancer (CRC). The aim of this matched case-control study was to explore circulating novel adipocytokines, such as serum visfatin, omentin-1 and vaspin levels in patients with CRC. Method: Serum visfatin, omentin-1, and vaspin levels were measured in 69 subjects (39 patients with colorectal cancer and 30 age- and sex-matched healthy controls) using enzyme-linked immunosorbent assay (ELISA) methods. Results: Compared with the controls, patients with CRC had significantly higher circulating omentin-1 (203.23 vs 9.12 ng/ml, p < 0.0001) visfatin (4.03 vs 2.01 ng/ml, p < 0.0001) and vaspin (0.54 vs 0.31 ng/ ml, p = 0.015) levels. After adjustment for covariates (age and body mass index), patients with CRC had significantly higher serum omentin-1 (p < 0.0001), visfatin (p < 0.0001), and vaspin (p = 0.040) levels than the control group. Furthermore, the results did not change when age and waist-to-hip ratio were considered as covariates in the general linear models. Conclusions: The observed higher levels of omentin-1, visfatin, and vaspin in patients with CRC, independent of measures of obesity, suggest that these adipocytokines may have a potential role in the development of CRC through mechanisms other than the indirect mechanisms that are active in the association between obesity and CRC

A Comparison of Verapamil and Digoxin for Heart Rate Control in Atrial Fibrillation

Purpose: Atrial fibrillation (AF) is one of the most common types of sustained dysrhythmia and there are some disagreements about its treatment. The goals of AF treatment include the control of ventricular rate, the establishment of sinus rhythm and the prevention of thromboembolic events. In this study, the effect of verapamil was compared to digoxin on heart rate control in patients with AF. Methods:This descriptive study was conducted in an emergency department (ED) in Iran. Sixty patients with a new onset AF and rapid ventricular response receiving digoxin or verapamil were included and observed. Results:Two thirty-patient groups receiving verapamil or digoxin were evaluated. The heart rate was significantly decreased in both groups (p = 0.002); however, the cardioversion was not noticed in both of them. The best rate control in verapamil and digoxin groups was observed after 5.9 mg (46.7%) and 0.6 mg (36.7%), respectively. Conclusion: Administration of verapamil in comparison with digoxin has no difference to control the heart rate in AF patients. It should be taken into consideration that prospective randomized studies should be conducted to identify the efficacy and select the best of these two drugs to treat AF patients

Force Open:Lightweight black box file repair

We present a novel approach for automatic repair of corrupted files that applies to any common file format and does not require knowledge of its structure. Our lightweight approach modifies the execution of a file viewer instead of the file data and makes use of instrumentation and execution hijacking, two techniques from software testing. It uses a file viewer as a black box and does not require access to its source code or any knowledge about its inner workings. We present our implementation of this approach and evaluate it on corrupted PNG, JPEG, and PDF files.ISSN:1742-2876ISSN:1873-202